Methods and devices for pain management

ABSTRACT

A method in which a location is determined on the skin that is proximate to a sensory nerve that is associated with a painful condition. At least one needle of a cryogenic device is inserted into the location on the skin such that the needle is proximate to the sensory nerve. The device is activated such that the at least one needle creates a cooling zone about the sensory nerve, thereby eliminating or reducing severity of the painful condition.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a Divisional of U.S. Ser. No. 14/025,527filed Sep. 12, 2013 (Allowed); which application claim the benefit ofU.S. Provisional Appln. Nos. 61/800,478 filed Mar. 15, 2013, and61/801,268 filed Mar. 15, 2013; the full disclosures which areincorporated herein by reference in their entirety for all purposes.

BACKGROUND OF THE INVENTION

The present invention is directed to medical devices, systems, andmethods, particularly for those which employ cold for treatment of painin a patient. Embodiments of the invention include cryogenic coolingneedles that can be advanced through skin or other tissues to inhibitneural transmission of pain signals.

Therapeutic treatment of chronic or acute pain is among the most commonreasons patients seek medical care. Chronic pain may be particularlydisabling, and the cumulative economic impact of chronic pain is huge. Alarge portion of the population that is over the age of 65 may sufferfrom any of a variety of health issues which can predispose them tochronic or acute pain. An even greater portion of the nursing homepopulation may suffer from chronic pain.

Current treatments for chronic pain may include pharmaceuticalanalgesics and electrical neurostimulation. While both these techniquesmay provide some level of relief, they can have significant drawbacks.For example, pharmaceuticals may have a wide range of systemic sideeffects, including gastrointestinal bleeding, interactions with otherdrugs, and the like. Opiod analgesics can be addictive, and may also ofthemselves be debilitating. The analgesic effects provided bypharmaceuticals may be relatively transient, making themcost-prohibitive for the aging population that suffers from chronicpain. While neurostimulators may be useful for specific applications,they generally involve surgical implantation, an expensive procedurewhich carries its own risks, side effects, contraindications, on-goingmaintenance issues, and the like.

In general, it would be advantageous to provide improved devices,systems, and methods for management of chronic and/or acute pain. Suchimproved techniques may avoid or decrease the systemic effects oftoxin-based neurolysis and pharmaceutical approaches, while decreasingthe invasiveness and/or collateral tissue damage of at least some knownpain treatment techniques.

BRIEF SUMMARY OF THE INVENTION

Some embodiments of the invention are related to a method in which alocation of a zone is determined with reference to the skin surfaceadjacent or proximate to a sensory nerve associated with a painfulcondition. At least one needle of a cryogenic device may be insertedthrough the skin and into the zone. The needle may be positionedadjacent to the sensory nerve. The device may be activated such that theat least one needle creates a cooling zone about the sensory nerve,thereby eliminating or reducing severity of the painful condition. Nervestimulation, ultrasound guidance, or other nerve localization orvisualization techniques are not used to determine the location in someembodiments but may be used in other embodiments.

Some embodiments of the invention are also related to a method in whichlocation is determined of a treatment zone with reference to the skinsurface that is proximate or adjacent to an infrapatellar branch of asaphenous nerve that is associated with osteo-arthritis of a knee of theleg and other painful conditions associated with the inferior aspect ofthe anterior knee. At least one needle of a cryogenic device may beinserted through the skin and positioned adjacent to the infrapatellarbranch. The device may be activated such that the at least one needlecreates a cooling zone about the infrapatellar branch, therebyeliminating or reducing severity of pain caused by the osteo-arthritis.In a similar method, branches of the anterior femoral cutaneous nerveand the lateral femoral cutaneous nerve may be treated.

In many embodiments, body landmarks are used to determine location ofthe zone.

In many embodiments, the treatment zone approximates a rectangle definedby: a first line/boundary laterally separated by a first predetermineddistance from a patellar tendon of the knee; a second line/boundaryparallel to the first line/boundary, the second line/boundary beinglaterally separated by a second predetermined distance from a lower poleof a patella of the knee; a third line/boundary transversely connectingthe first and second line/boundaries, the third line/boundary extendingfrom a tibial tubercle of the knee; and a fourth line/boundarytransversely connecting the first and second line/boundary, the fourthline/boundary extending from a mid-portion of the patella.

In some embodiments the first predetermined distance may range between25 and 60 mm. In some embodiments the second predetermined distance mayrange between 30 and 70 mm.

In many embodiments, the at least one needle is used repeatedly tocreate a plurality of cooling zones along the second line between thethird and fourth lines.

In many embodiments, the at least one needle is used repeatedly tocreate a plurality of cooling zones along the first and second linesbetween the third and fourth lines.

In many embodiments, the cryogenic device comprises a plurality ofneedles, and plurality of needles of the cryogenic device are insertedinto the treatment zone to create the cooling zone.

In many embodiments, the plurality of needles is used repeatedly tocreate a plurality of cooling zones along the second line between thethird and fourth lines.

In many embodiments, the plurality of needles is used repeatedly tocreate a plurality of cooling zones along the first and second linesbetween the third and fourth lines.

In many embodiments, the cooling zone causes Wallerian degeneration tooccur at the infrapatellar branch.

In some embodiments the at least one needle may be inserted into theskin along an insertion axis and may be positioned adjacent a targettissue by: bending the needle after insertion through the skin away fromthe insertion axis, and advancing the needle to the target tissue.Optionally, the needle may have a blunt distal tip.

Many embodiments of the invention relate to a system having a bodyhaving a handle, a coolant supply path within the body, and at least onecryogenic needle supported by the handle and coupled to the coolantsupply path, system being adapted to target a particular sensory nerve.For example, an infrapatellar branch of a saphenous nerve.

In many embodiments, the system is used without the benefit of nervestimulation to locate the particular sensory nerve. However, in otherembodiments, the system includes a device for nerve stimulation.

In many embodiments, the system can be adpated by configuring acontroller of the system to cause the needle to generate a cooling zonefor a particalar period of time, temperature, and size to affect theparticular sensory nerve. These values can be adjusted in real-timeusing feedback provided by sensory detection and/or interpolationalcalculations of heater power draw.

In many embodiments, a plurality of needles is supported by the handleand coupled to the handle.

In many embodiments, the at least one needle, or each needle of theplurality, is of a particular size to target an infrapatellar branch ofa saphenous nerve. This can be achieved by using a needle with aspecific length and diameter.

In many embodiments, the at least one needle, or each needle of theplurality, includes a thermally conductive coating that is of aparticular length for protecting tissue above the particular sensorynerve. The conductive coating can be coupled to a heater.

Some embodiments relate to a method in which location of a treatmentzone is located on skin that is proximate to an infrapatellar branch ofa saphenous nerve that is associated with osteo-arthritis of a knee ofthe leg. The infrapatellar branch of the saphenous nerve is treated,thereby eliminating or reducing severity of pain caused by theosteo-arthritis. In many embodiments, thermal energy is used to treatthe nerve. In some embodiments, RF is used to create the thermal energy.In many embodiments, the treatment is made with an injection of asubstance. In many embodiments, the substance is phenol. In manyembodiments, the substance is ethyl alcohol.

Some embodiments may relate to a method in which a treatment surface ofa cryogenic device is positioned within a treatment zone below skin of apatient body. The treatment zone is proximate a selected branch of anerve associated with osteo-arthritis of a joint. This is done byidentifying a region of the skin with reference to hard tissuestructures identifiable tactilely and/or visibly through the skin andthen advancing at least one probe of a cryogenic device through the skinand into the treatment zone underlying the region.

The device may be activated such that the at least one probe creates acooling zone about the selected branch, the cooling zone inducingWallerian degeneration of the selected branch so as to eliminate orreduce severity of pain caused by the osteoarthritis.

In yet another embodiment of the invention, a system is provided fortreating osteoarthritis of a knee of a leg of a patient. The system mayinclude a guide for identifying treatment zone with reference to a skinsurface and a treatment probe configured for directing a treatment underthe skin surface with reference to the zone. The treatment may beconfigured to modulate an infrapatellar branch of the saphenous nerveassociated with osteoarthritis of a knee of a leg.

In some embodiments, the guide may be placed on the skin surfacerelative to body landmarks. Optionally, the guide may be configured toidentify a zone with an uppermost/superior boundary defined by a midlineof a patella of the leg. In some embodiments, the guide may beconfigured to identify a zone with a bottommost/inferior boundarydefined by a tibial tubercle of the leg. In some embodiments, the guidemay be configured to identify a zone with a medial boundary defined by afirst distance lateral to a medial aspect of the patellar tendon of theleg. In some embodiments, the guide may be configured to identify a zonewith a lateral boundary defined by a second distance lateral to a lowerpole of a patella of the leg. In some embodiments the first distance maybe between 25 and 60 mm. In some embodiments the second distance may bebetween 30 and 70 mm.

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a self-contained subdermal cryogenicremodeling probe and system, according to some embodiments of theinvention;

FIG. 1B is a partially transparent perspective view of theself-contained probe of FIG. 1A, showing internal components of thecryogenic remodeling system and schematically illustrating replacementtreatment needles for use with the disposable probe according to someembodiments of the invention;

FIG. 2A schematically illustrates exemplary components that may beincluded in the treatment system;

FIG. 2B is a cross-sectional view of the system of FIG. 1A, according tosome embodiments of the invention;

FIGS. 2C and 2D are cross-sectional views showing exemplary operationalmodes of the system of FIG. 2B;

FIGS. 3A-3E illustrate an exemplary embodiment of a clad needle probe,according to some embodiments of the invention;

FIGS. 4A-4C illustrate an exemplary method of introducing a cryogenicprobe to a treatment area, according to some embodiments of theinvention;

FIG. 4D illustrates an alternative exemplary embodiment of a sheath,according to some embodiments of the invention;

FIG. 5 illustrates an exemplary insulated cryoprobe, according to someembodiments of the invention;

FIGS. 6-9 illustrate exemplary embodiments of cryofluid delivery tubes,according to some embodiments of the invention;

FIG. 10 illustrates an example of blunt tipped cryoprobe, according tosome embodiments of the invention;

FIGS. 11 and 12 illustrate exemplary actuatable cryoprobes, according tosome embodiments of the invention;

FIG. 13 is a flow chart illustrating an exemplary algorithm for heatingthe needle probe of FIG. 3A, according to some embodiment of theinvention;

FIG. 14 is a flow chart schematically illustrating an exemplary methodfor treatment using the disposable cryogenic probe and system of FIGS.1A and 1B, according to some embodiments of the invention;

FIG. 15 is illustration of the infrapatellar branch of a saphenousnerve, according to some embodiments of the invention;

FIG. 16A and FIG. 16B are illustrations of the interconnections of thesaphenous nerve;

FIG. 17 is another illustration of the interconnections of the saphenousnerve;

FIG. 18 is an illustration of the position and division of the ISN;

FIG. 19 is illustration of possible landmarks for locating the ISN andan exemplary treatment zone;

FIG. 20 is an illustration of an exemplary treatment zone according tosome embodiments of the present invention;

FIG. 21A and FIG. 21B are illustrates of an exemplary treatment templateor guide according to some embodiments of the present invention;

FIG. 22 is a chart from a study summarizing WOMAC scores before andafter treatment of osteoarthritis patients according to some embodimentsof the present invention;

FIG. 23 is a chart illustrating the number of subjects reportingimprovement in WOMAC pain scores 7 days after treatment;

FIG. 24 is a chart showing VAS scores over a follow up period;

FIG. 25 is a chart showing the duration of treatment benefit during afollow up period;

FIG. 26 is a chart summarizing the percent of knees reportinganticipated observations; and

FIG. 27A and FIG. 27B are charts summarizing the patient's subjectiveassessment of the treatment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides improved medical devices, systems, andmethods. Embodiments of the invention may facilitate remodeling oftarget tissues disposed at and below the skin, optionally to treat painassociated with a sensory nerve. Embodiments of the invention mayutilize a handheld refrigeration system that can use a commerciallyavailable cartridge of fluid refrigerant. Refrigerants well suited foruse in handheld refrigeration systems may include nitrous oxide andcarbon dioxide. These can achieve temperatures approaching −90° C.

Sensory nerves and associated tissues may be temporarily immobilizedusing moderately cold temperatures of 10° C. to −5° C. withoutpermanently disabling the tissue structures. Using an approach similarto that employed for identifying structures associated with atrialfibrillation, a needle probe or other treatment device can be used toidentify a target tissue structure in a diagnostic mode with thesemoderate temperatures, and the same probe (or a different probe) canalso be used to provide a longer term or permanent treatment, optionallyby ablating the target tissue zone and/or inducing apoptosis attemperatures from about −5° C. to about −50° C. In some embodiments,apoptosis may be induced using treatment temperatures from about −1° C.to about −15° C., or from about −1° C. to about −19° C., optionally soas to provide a longer lasting treatment that limits or avoidsinflammation and mobilization of skeletal muscle satellite repair cells.In some embodiments, axonotmesis with Wallerian degeneration of asensory nerve is desired, which may be induced using treatmenttemperatures from about −20° C. to about −100° C. Hence, the duration ofthe treatment efficacy of such subdermal cryogenic treatments may beselected and controlled, with colder temperatures, longer treatmenttimes, and/or larger volumes or selected patterns of target tissuedetermining the longevity of the treatment. Additional description ofcryogenic cooling methods and devices may be found in commonly assignedU.S. Pat. No. 7,713,266 entitled “Subdermal Cryogenic Remodeling ofMuscle, Nerves, Connective Tissue, and/or Adipose Tissue (Fat)”, U.S.Pat. No. 7,850,683 entitled “Subdermal Cryogenic Remodeling of Muscles,Nerves, Connective Tissue, and/or Adipose Tissue (Fat)”, U.S. patentapplication Ser. No. 13/325,004 entitled “Method for ReducingHyperdynamic Facial Wrinkles”, and U.S. Pub. No. 2009/0248001 entitled“Pain Management Using Cryogenic Remodeling,” the full disclosures ofwhich are each incorporated by reference herein.

Referring now to FIGS. 1A and 1B, a system for cryogenic remodeling herecomprises a self-contained probe handpiece generally having a proximalend 12 and a distal end 14. A handpiece body or housing 16 has a sizeand ergonomic shape suitable for being grasped and supported in asurgeon's hand or other system operator. As can be seen most clearly inFIG. 1B, a cryogenic cooling fluid supply 18, a supply valve 32 andelectrical power source 20 are found within housing 16, along with acircuit 22 having a processor for controlling cooling applied byself-contained system 10 in response to actuation of an input 24.Alternatively, electrical power can be applied through a cord from aremote power source. Power source 20 also supplies power to heaterelement 44 in order to heat the proximal region of probe 26 which maythereby help to prevent unwanted skin damage, and a temperature sensor48 adjacent the proximal region of probe 26 helps monitor probetemperature. Additional details on the heater 44 and temperature sensor48 are described in greater detail below. When actuated, supply valve 32controls the flow of cryogenic cooling fluid from fluid supply 18. Someembodiments may, at least in part, be manually activated, such asthrough the use of a manual supply valve and/or the like, so thatprocessors, electrical power supplies, and the like may not be required.

Extending distally from distal end 14 of housing 16 may be atissue-penetrating cryogenic cooling probe 26. Probe 26 is thermallycoupled to a cooling fluid path extending from cooling fluid source 18,with the exemplary probe comprising a tubular body receiving at least aportion of the cooling fluid from the cooling fluid source therein. Theexemplary probe 26 may comprise a 30 g needle having a sharpened distalend that is axially sealed. Probe 26 may have an axial length betweendistal end 14 of housing 16 and the distal end of the needle of betweenabout 0.5 mm and 15 cm, preferably having a length from about 3 mm toabout 10 mm. Such needles may comprise a stainless steel tube with aninner diameter of about 0.006 inches and an outer diameter of about0.012 inches, while alternative probes may comprise structures havingouter diameters (or other lateral cross-sectional dimensions) from about0.006 inches to about 0.100 inches. Generally, needle probe 26 maycomprise a 16 g or smaller size needle, often comprising a 20 g needleor smaller, typically comprising a 25, 26, 27, 28, 29, or 30 g orsmaller needle.

In some embodiments, probe 26 may comprise two or more needles arrangedin a linear array, such as those disclosed in previously incorporatedU.S. Pat. No. 7,850,683. Another exemplary embodiment of a probe havingmultiple needle probe configurations allow the cryogenic treatment to beapplied to a larger or more specific treatment area. Other needleconfigurations that facilitate controlling the depth of needlepenetration and insulated needle embodiments are disclosed in commonlyassigned U.S. Patent Publication No. 2008/0200910 entitled “Replaceableand/or Easily Removable Needle Systems for Dermal and TransdermalCryogenic Remodeling,” the entire content of which is incorporatedherein by reference. Multiple needle arrays may also be arrayed inalternative configurations such as a triangular or square array.

Arrays may be designed to treat a particular region of tissue, or toprovide a uniform treatment within a particular region, or both. In someembodiments needle 26 may be releasably coupled with body 16 so that itmay be replaced after use with a sharper needle (as indicated by thedotted line) or with a needle having a different configuration. Inexemplary embodiments, the needle may be threaded into the body, pressfit into an aperture in the body or have a quick disconnect such as adetent mechanism for engaging the needle with the body. A quickdisconnect with a check valve may be advantageous since it may permitdecoupling of the needle from the body at any time without excessivecoolant discharge. This can be a useful safety feature in the event thatthe device fails in operation (e.g. valve failure), allowing an operatorto disengage the needle and device from a patient's tissue withoutexposing the patient to coolant as the system depressurizes. Thisfeature may also be advantageous because it allows an operator to easilyexchange a dull needle with a sharp needle in the middle of a treatment.One of skill in the art will appreciate that other coupling mechanismsmay be used.

Addressing some of the components within housing 16, the exemplarycooling fluid supply 18 may comprise a canister, sometimes referred toherein as a cartridge, containing a liquid under pressure, with theliquid preferably having a boiling temperature of less than 37° C. atone atmosphere of pressure. When the fluid is thermally coupled to thetissue-penetrating probe 26, and the probe is positioned within thepatient so that an outer surface of the probe is adjacent to a targettissue, the heat from the target tissue evaporates at least a portion ofthe liquid and the enthalpy of vaporization cools the target tissue. Asupply valve 32 may be disposed along the cooling fluid flow pathbetween canister 18 and probe 26, or along the cooling fluid path afterthe probe so as to limit coolant flow thereby regulating thetemperature, treatment time, rate of temperature change, or othercooling characteristics. The valve will often be powered electricallyvia power source 20, per the direction of processor 22, but may at leastin part be manually powered. The exemplary power source 20 comprises arechargeable or single-use battery. Additional details about valve 32are disclosed below and further disclosure on the power source 20 may befound in commonly assigned Int'l Pub. No. WO 2010/075438 entitled“Integrated Cryosurgical Probe Package with Fluid Reservoir and LimitedElectrical Power Source,” the entire contents of which are incorporatedherein by reference.

The exemplary cooling fluid supply 18 may comprise a single-usecanister. Advantageously, the canister and cooling fluid therein may bestored and/or used at (or even above) room temperature. The canister mayhave a frangible seal or may be refillable, with the exemplary canistercontaining liquid nitrous oxide, N₂O. A variety of alternative coolingfluids might also be used, with exemplary cooling fluids includingfluorocarbon refrigerants and/or carbon dioxide. The quantity of coolingfluid contained by canister 18 will typically be sufficient to treat atleast a significant region of a patient, but will often be less thansufficient to treat two or more patients. An exemplary liquid N₂Ocanister might contain, for example, a quantity in a range from about 1gram to about 40 grams of liquid, more preferably from about 1 gram toabout 35 grams of liquid, and even more preferably from about 7 grams toabout 30 grams of liquid.

Processor 22 will typically comprise a programmable electronicmicroprocessor embodying machine readable computer code or programminginstructions for implementing one or more of the treatment methodsdescribed herein. The microprocessor will typically include or becoupled to a memory (such as a non-volatile memory, a flash memory, aread-only memory (“ROM”), a random access memory (“RAM”), or the like)storing the computer code and data to be used thereby, and/or arecording media (including a magnetic recording media such as a harddisk, a floppy disk, or the like; or an optical recording media such asa CD or DVD) may be provided. Suitable interface devices (such asdigital-to-analog or analog-to-digital converters, or the like) andinput/output devices (such as USB or serial I/O ports, wirelesscommunication cards, graphical display cards, and the like) may also beprovided. A wide variety of commercially available or specializedprocessor structures may be used in different embodiments, and suitableprocessors may make use of a wide variety of combinations of hardwareand/or hardware/software combinations. For example, processor 22 may beintegrated on a single processor board and may run a single program ormay make use of a plurality of boards running a number of differentprogram modules in a wide variety of alternative distributed dataprocessing or code architectures.

Referring now to FIG. 2A, schematic 11 shows a simplified diagram ofcryogenic cooling fluid flow and control. The flow of cryogenic coolingfluid from fluid supply 18 may be controlled by a supply valve 32.Supply valve 32 may comprise an electrically actuated solenoid valve, amotor actuated valve or the like operating in response to controlsignals from controller 22, and/or may comprise a manual valve.Exemplary supply valves may comprise structures suitable for on/offvalve operation, and may provide venting of the fluid source and/or thecooling fluid path downstream of the valve when cooling flow is haltedso as to limit residual cryogenic fluid vaporization and cooling.Additionally, the valve may be actuated by the controller in order tomodulate coolant flow to provide high rates of cooling in some instanceswhere it is desirable to promote necrosis of tissue such as in malignantlesions and the like or slow cooling which promotes ice formationbetween cells rather than within cells when necrosis is not desired.More complex flow modulating valve structures might also be used inother embodiments. For example, other applicable valve embodiments aredisclosed in previously incorporated U.S. Pub. No. 2008/0200910.

Still referring to FIG. 2A, an optional heater (not illustrated) may beused to heat cooling fluid supply 18 so that heated cooling fluid flowsthrough valve 32 and through a lumen 34 of a cooling fluid supply tube36. In some embodiments a safety mechanism can be included so that thecooling supply is not overheated. Examples of such embodiments aredisclosed in commonly assigned International Publication No. WO2010075438, the entirety of which is incorporated by reference herein.

Supply tube 36 is, at least in part, disposed within a lumen 38 ofneedle 26, with the supply tube extending distally from a proximal end40 of the needle toward a distal end 42. The exemplary supply tube 36comprises a fused silica tubular structure (not illustrated) having apolymer coating and extending in cantilever into the needle lumen 38.Supply tube 36 may have an inner lumen with an effective inner diameterof less than about 200 μm, the inner diameter often being less thanabout 100 μm, and typically being less than about 40 μm. Exemplaryembodiments of supply tube 36 have inner lumens of between about 15 and50 μm, such as about 30 μm. An outer diameter or size of supply tube 36will typically be less than about 1000 μm, often being less than about800 μm, with exemplary embodiments being between about 60 and 150 μm,such as about 90 μm or 105 μm. The tolerance of the inner lumen diameterof supply tubing 36 will preferably be relatively tight, typically beingabout +/−10 μm or tighter, often being +/−5 μm or tighter, and ideallybeing +/−3 μm or tighter, as the small diameter supply tube may providethe majority of (or even substantially all of) the metering of thecooling fluid flow into needle 26. Additional details on various aspectsof needle 26 along with alternative embodiments and principles ofoperation are disclosed in greater detail in U.S. Patent Publication No.2008/0154254 entitled “Dermal and Transdermal Cryogenic MicroprobeSystems and Methods,” the entire contents of which are incorporatedherein by reference. Previously incorporated U.S. Patent Publication No.2008/0200910 also discloses additional details on the needle 26 alongwith various alternative embodiments and principles of operation.

The cooling fluid injected into lumen 38 of needle 26 will typicallycomprise liquid, though some gas may also be injected. At least some ofthe liquid vaporizes within needle 26, and the enthalpy of vaporizationcools the needle and also the surrounding tissue engaged by the needle.An optional heater 44 (illustrated in FIG. 1B) may be used to heat theproximal region of the needle in order to prevent unwanted skin damagein this area, as discussed in greater detail below. Controlling apressure of the gas/liquid mixture within needle 26 substantiallycontrols the temperature within lumen 38, and hence the treatmenttemperature range of the tissue. A relatively simple mechanical pressurerelief valve 46 may be used to control the pressure within the lumen ofthe needle, with the exemplary valve comprising a valve body such as aball bearing, urged against a valve seat by a biasing spring. Anexemplary relief valve is disclosed in U.S. Provisional PatentApplication No. 61/116,050 previously incorporated herein by reference.Thus, the relief valve may allow better temperature control in theneedle, minimizing transient temperatures. Further details on exhaustvolume are disclosed in previously incorporated U.S. Pat. Pub. No.2008/0200910.

The heater 44 may be thermally coupled to a thermally responsive element50, which is supplied with power by the controller 22 and thermallycoupled to a proximal portion of the needle 26. The thermally responsiveelement 50 can be a block constructed from a material of high thermalconductivity and low heat capacity, such as aluminum. A firsttemperature sensor 52 (e.g., thermistor, thermocouple) can also bethermally coupled the thermally responsive element 50 andcommunicatively coupled to the controller 22. A second temperaturesensor 53 can also be positioned near the heater 44, for example, suchthat the first temperature sensor 52 and second temperature sensor 53are placed in different positions within the thermally responsiveelement 50. In some embodiments, the second temperature sensor 53 isplaced closer to a tissue contacting surface than the first temperaturesensor 52 is placed in order to provide comparative data (e.g.,temperature differential) between the sensors 52, 53. The controller 22can be configured to receive temperature information of the thermallyresponsive element 50 via the temperature sensor 52 in order to providethe heater 44 with enough power to maintain the thermally responsiveelement 50 at a particular temperature.

The controller 22 can be further configured to monitor power draw fromthe heater 44 in order to characterize tissue type, perform devicediagnostics, and/or provide feedback for a tissue treatment algorithm.This can be advantageous over monitoring temperature alone, since powerdraw from the heater 44 can vary greatly while temperature of thethermally responsive element 50 remains relatively stable. For example,during treatment of target tissue, maintaining the thermally responsiveelement 50 at 40° C. during a cooling cycle may take 1.0 W initially(for a needle <10 mm in length) and is normally expected to climb to 1.5W after 20 seconds, due to the needle 26 drawing in surrounding heat. Anindication that the heater is drawing 2.0 W after 20 seconds to maintain40° C. can indicate that an aspect of the system 10 is malfunctioningand/or that the needle 26 is incorrectly positioned. Correlations withpower draw and correlated device and/or tissue conditions can bedetermined experimentally to determine acceptable treatment powerranges.

In some embodiments, it may be preferable to limit frozen tissue that isnot at the treatment temperature, i.e., to limit the size of a formedcooling zone within tissue. Such cooling zones may be associated with aparticular physical reaction, such as the formation of an ice-ball, orwith a particular temperature profile or temperature volume gradientrequired to therapeutically affect the tissue therein. To achieve this,metering coolant flow could maintain a large thermal gradient at itsoutside edges. This may be particularly advantageous in applications forcreating an array of connected cooling zones (i.e., fence) in atreatment zone, as time would be provided for the treatment zone tofully develop within the fenced in portion of the tissue, while theouter boundaries maintained a relatively large thermal gradient due tothe repeated application and removal of refrigeration power. This couldprovide a mechanism within the body of tissue to thermally regulate thetreatment zone and could provide increased ability to modulate thetreatment zone at a prescribed distance from the surface of the skin. Arelated treatment algorithm could be predefined, or it could be inresponse to feedback from the tissue.

Such feedback could be temperature measurements from the needle 26, orthe temperature of the surface of the skin could be measured. However,in many cases monitoring temperature at the needle 26 is impractical dueto size constraints. To overcome this, operating performance of thesensorless needle 26 can be interpolated by measuring characteristics ofthermally coupled elements, such as the thermally responsive element 50.

Additional methods of monitoring cooling and maintaining an unfrozenportion of the needle include the addition of a heating element and/ormonitoring element into the needle itself. This could consist of a smallthermistor or thermocouple, and a wire that could provide resistiveheat. Other power sources could also be applied such as infrared light,radiofrequency heat, and ultrasound. These systems could also be appliedtogether dependent upon the control of the treatment zone desired.

Alternative methods to inhibit excessively low transient temperatures atthe beginning of a refrigeration cycle might be employed instead of ortogether with the limiting of the exhaust volume. For example, thesupply valve 32 might be cycled on and off, typically by controller 22,with a timing sequence that would limit the cooling fluid flowing sothat only vaporized gas reached the needle lumen 38 (or a sufficientlylimited amount of liquid to avoid excessive dropping of the needle lumentemperature). This cycling might be ended once the exhaust volumepressure was sufficient so that the refrigeration temperature would bewithin desired limits during steady state flow. Analytical models thatmay be used to estimate cooling flows are described in greater detail inpreviously incorporated U.S. Patent Pub. No. 2008/0154254.

FIG. 2B shows a cross-section of the housing 16. This embodiment of thehousing 16 may be powered by an external source, hence the attachedcable, but could alternatively include a portable power source. Asshown, the housing includes a cartridge holder 50. The cartridge holder50 includes a cartridge receiver 52, which may be configured to hold apressured refrigerant cartridge 18. The cartridge receiver 52 includesan elongated cylindrical passage 54, which is dimensioned to hold acommercially available cooling fluid cartridge 18. A distal portion ofthe cartridge receiver 52 includes a filter device 56, which has anelongated conical shape. In some embodiments, the cartridge holder 50may be largely integrated into the housing 16 as shown, however, inalternative embodiments, the cartridge holder 50 is a wholly separateassembly, which may be pre-provided with a coolant fluid source 18.

The filter device 56 may fluidly couple the coolant fluid source(cartridge) 18 at a proximal end to the valve 32 at a distal end. Thefilter device 56 may include at least one particulate filter 58. In theshown embodiment, a particulate filter 58 at each proximal and distalend of the filter device 56 may be included. The particulate filter 58can be configured to prevent particles of a certain size from passingthrough. For example, the particulate filter 58 can be constructed as amicroscreen having a plurality of passages less than 2 microns in width,and thus particles greater than 2 microns would not be able to pass.

The filter device 56 also includes a molecular filter 60 that isconfigured to capture fluid impurities. In some embodiments, themolecular filter 60 is a plurality of filter media (e.g., pellets,powder, particles) configured to trap molecules of a certain size. Forexample, the filter media can comprise molecular sieves having poresranging from 1-20 Å. In another example, the pores have an average sizeof 5 Å. The molecular filter 60 can have two modalities. In a firstmode, the molecular filter 60 will filter fluid impurities received fromthe cartridge 18. However, in another mode, the molecular filter 60 cancapture impurities within the valve 32 and fluid supply tube 36 when thesystem 10 is not in use, i.e., when the cartridge 18 is not fluidlyconnected to the valve 32.

Alternatively, the filter device 56 can be constructed primarily fromePTFE (such as a GORE material), sintered polyethylene (such as made byPOREX), or metal mesh. The pore size and filter thickness can beoptimized to minimize pressure drop while capturing the majority ofcontaminants. These various materials can be treated to make ithydrophobic (e.g., by a plasma treatment) and/or oleophobic so as torepel water or hydrocarbon contaminants.

It has been found that in some instances fluid impurities may leach outfrom various aspects of the system 10. These impurities can includetrapped moisture in the form of water molecules and chemical gasses. Thepresence of these impurities is believed to hamper cooling performanceof the system 10. The filter device 56 can act as a desiccant thatattracts and traps moisture within the system 10, as well as chemicalsout gassed from various aspects of the system 10. Alternately thevarious aspects of the system 10 can be coated or plated withimpermeable materials such as a metal.

As shown in FIG. 2B and in more detail in FIG. 2C and FIG. 2D, thecartridge 18 can be held by the cartridge receiver 52 such that thecartridge 18 remains intact and unpunctured. In this inactive mode, thecartridge may not be fluidly connected to the valve 32. A removablecartridge cover 62 can be attached to the cartridge receiver 52 suchthat the inactive mode is maintained while the cartridge is held by thesystem 10.

In use, the cartridge cover 62 can be removed and supplied with acartridge containing a cooling fluid. The cartridge cover 62 can then bereattached to the cartridge receiver 52 by turning the cartridge cover62 until female threads 64 of the cartridge cover 62 engage with malethreads of the cartridge receiver 52. The cartridge cover 62 can beturned until resilient force is felt from an elastic seal 66, as shownin FIG. 2C. To place the system 10 into use, the cartridge cover 62 canbe further turned until the distal tip of the cartridge 18 is puncturedby a puncture pin connector 68, as shown in FIG. 2D. Once the cartridge18 is punctured, cooling fluid may escape the cartridge by flowingthrough the filter device 56, where the impurities within the coolingfluid may be captured. The purified cooling fluid then passes to thevalve 32, and onto the coolant supply tube 36 to cool the probe 26. Insome embodiments the filter device, or portions thereof, may bereplaceable.

In some embodiments, the puncture pin connector 68 can have a two-wayvalve (e.g., ball/seat and spring) that is closed unless connected tothe cartridge. Alternately, pressure can be used to open the valve. Thevalve closes when the cartridge is removed. In some embodiments, theremay be a relief valve piloted by a spring which is balanced byhigh-pressure nitrous when the cartridge is installed and the system ispressurized, but allows the high-pressure cryogen to vent when thecryogen is removed. In addition, the design can include a vent port thatvents cold cryogen away from the cartridge port. Cold venting cryogenlocally can cause condensation in the form of liquid water to form fromthe surrounding environment. Liquid water or water vapor entering thesystem can hamper the cryogenic performance. Further, fluid carryingportions of the cartridge receiver 52 can be treated (e.g., plasmatreatment) to become hydrophobic and/or oleophobic so as to repel wateror hydrocarbon contaminants.

Turning now to FIG. 3A and FIG. 3B, an exemplary embodiment of probe 300having multiple needles 302 is described. In FIG. 3A, probe housing 316includes threads 306 that allow the probe to be threadably engaged withthe housing 16 of a cryogenic device. O-rings 308 fluidly seal the probehousing 316 with the device housing 16 and prevent coolant from leakingaround the interface between the two components. Probe 300 includes anarray of three distally extending needle shafts 302, each having asharpened, tissue penetrating tip 304. Using three linearly arrangedneedles allows a greater area of tissue to be treated as compared with asingle needle. In use, coolant flows through lumens 310 into the needleshafts 302 thereby cooling the needle shafts 302. Ideally, only thedistal portion of the needle shaft 302 would be cooled so that only thetarget tissue receives the cryogenic treatment. However, as the coolingfluid flows through the probe 300, probe temperature decreasesproximally along the length of the needle shafts 302 towards the probehub 318. The proximal portion of needle shaft 302 and the probe hub 318contact skin and may become very cold (e.g. −20° C. to −25° C.) and thiscan damage the skin in the form of blistering or loss of skinpigmentation. Therefore it would be desirable to ensure that theproximal portion of needle shaft 302 and hub 318 remains warmer than thedistal portion of needle shaft 302. A proposed solution to thischallenge is to include a heater element 314 that can heat the proximalportion of needle shaft 302 and an optional temperature sensor 312 tomonitor temperature in this region. To further this, a proximal portionof the needle shaft 302 can be coated with a highly thermally conductivematerial, e.g., gold, that is conductively coupled to both the needleshaft 302 and heater element 314. Details of this construction aredisclosed below.

In the exemplary embodiment of FIG. 3A, resistive heater element 314 isdisposed near the needle hub 318 and near a proximal region of needleshaft 302. The resistance of the heater element is preferably 1 Ω to 1KΩ, and more preferably from 5 Ω to 50 Ω. Additionally, a temperaturesensor 312 such as a thermistor or thermocouple is also disposed in thesame vicinity. Thus, during a treatment as the needles cool down, theheater 314 may be turned on in order to heat the hub 318 and proximalregion of needle shaft 302, thereby preventing this portion of thedevice from cooling down as much as the remainder of the needle shaft302. The temperature sensor 312 may provide feedback to controller 22and a feedback loop can be used to control the heater 314. The coolingpower of the nitrous oxide may eventually overcome the effects of theheater, therefore the microprocessor may also be programmed with awarning light and/or an automatic shutoff time to stop the coolingtreatment before skin damage occurs. An added benefit of using such aheater element is the fact that the heat helps to moderate the flow ofcooling fluid into the needle shaft 302 helping to provide more uniformcoolant mass flow to the needles shaft 302 with more uniform coolingresulting.

The embodiment of FIG. 3A illustrates a heater fixed to the probe hub.In other embodiments, the heater may float, thereby ensuring proper skincontact and proper heat transfer to the skin. Examples of floatingheaters are disclosed in commonly assigned Int'l Pub. No. WO 2010/075448entitled “Skin Protection for Subdermal Cryogenic Remodeling forCosmetic and Other Treatments,” the entirety of which is incorporated byreference herein.

In this exemplary embodiment, three needles are illustrated. One ofskill in the art will appreciate that a single needle may be used, aswell as two, four, five, six, or more needles may be used. When aplurality of needles are used, they may be arranged in any number ofpatterns. For example, a single linear array may be used, or a twodimensional or three dimensional array may be used. Examples of twodimensional arrays include any number of rows and columns of needles(e.g. a rectangular array, a square array, elliptical, circular,triangular, etc.), and examples of three dimensional arrays includethose where the needle tips are at different distances from the probehub, such as in an inverted pyramid shape.

FIG. 3B illustrates a cross-section of the needle shaft 302 of needleprobe 300. The needle shaft can be conductively coupled (e.g., welded,conductively bonded, press fit) to a conductive heater 314 to enableheat transfer therebetween. The needle shaft 302 is generally a small(e.g., 20-30 gauge) closed tip hollow needle, which can be between about0.2 mm and 15 cm, preferably having a length from about 0.3 cm to about1.5 cm. The conductive heater element 314 can be housed within aconductive block 315 of high thermally conductive material, such asaluminum and include an electrically insulated coating, such as Type IIIanodized coating to electrically insulate it without diminishing itsheat transfer properties. The conductive block 315 can be heated by aresister or other heating element (e.g. cartridge heater, nichrome wire,etc.) bonded thereto with a heat conductive adhesive, such as epoxy. Athermistor can be coupled to the conductive block 315 with heatconductive epoxy allows temperature monitoring. Other temperaturesensors may also be used, such as a thermocouple.

A cladding 320 of conductive material is directly conductively coupledto the proximal portion of the shaft of the needle 302, which can bestainless steel. In some embodiments, the cladding 320 is a layer ofgold, or alloys thereof, coated on the exterior of the proximal portionof the needle shaft 302. In some embodiments, the exposed length ofcladding 320 on the proximal portion of the needle is 2-100 mm. In someembodiments, the cladding 320 can be of a thickness such that the cladportion has a diameter ranging from 0.017-0.020 in., and in someembodiments 0.0182 in. Accordingly, the cladding 320 can be conductivelycoupled to the material of the needle 302, which can be less conductive,than the cladding 320. The cladding 320 may modify the lateral forcerequired to deflect or bend the needle 26. Cladding 320 may be used toprovide a stiffer needle shaft along the proximal end in order to moreeasily transfer force to the leading tip during placement and allow thedistal portion of the needle to deflect more easily when it isdissecting a tissue interface within the body. The stiffness of needle26 can vary from one end to the other end by other means such asmaterial selection, metal tempering, variation of the inner diameter ofthe needle 26, or segments of needle shaft joined together end-to-end toform one contiguous needle 26. In some embodiments, increasing thestiffness of the distal portion of the needle 26 can be used to flex theproximal portion of the needle to access difficult treatment sites as inthe case of upper limb spasticity where bending of the needle outsidethe body may be used to access a target peripheral nerve along thedesired tissue plane.

In some embodiments, the cladding 320 can include sub-coatings (e.g.,nickel) that promote adhesion of an outer coating that would otherwisenot bond well to the needle shaft 302. Other highly conductive materialscan be used as well, such as copper, silver, aluminum, and alloysthereof. In some embodiments, a protective polymer or metal coating cancover the cladding to promote biocompatibility of an otherwisenon-biocompatible but highly conductive cladding material. Such abiocompatible coating however, would be applied to not disruptconductivity between the conductive block 315. In some embodiments, aninsulating layer, such as a ceramic material, is coated over thecladding 320, which remains conductively coupled to the needle shaft302.

In use, the cladding 320 can transfer heat to the proximal portion ofthe needle 302 to prevent directly surrounding tissue from dropping tocryogenic temperatures. Protection can be derived from heating thenon-targeting tissue during a cooling procedure, and in some embodimentsbefore the procedure as well. The mechanism of protection may beproviding heat to pressurized cryogenic cooling fluid passing within theproximal portion of the needle to affect complete vaporization of thefluid. Thus, the non-target tissue in contact with the proximal portionof the needle shaft 302 does not need to supply heat, as opposed totarget tissue in contact with the distal region of the needle shaft 302.To help further this effect, in some embodiments the cladding 320 iscoating within the interior of the distal portion of the needle, with orwithout an exterior cladding. To additionally help further this effect,in some embodiments, the distal portion of the needle can be thermallyisolated from the proximal portion by a junction, such as a ceramicjunction. While in some further embodiments, the entirety of theproximal portion is constructed from a more conductive material than thedistal portion.

In use, it has been determined experimentally that the cladding 320 canhelp limit formation of a cooling zone to the distal portion of theneedle shaft 302, which tends to demarcate at a distal end of thecladding 320. Accordingly, cooling zones are formed only about thedistal portions of the needles. Thus, non-target tissue in directcontact with proximal needle shafts remain protected from effects ofcryogenic temperatures. Such effects can include discoloration andblistering of the skin. Such cooling zones may be associated with aparticular physical reaction, such as the formation of an ice-ball, orwith a particular temperature required to therapeutically affect thetissue therein.

Standard stainless steel needles and gold clad steel needles were testedin porcine muscle and fat. Temperatures were recorded measured 2 mm fromthe proximal end of the needle shaft, about where the cladding distallyterminates, and at the distal tip of the needles. As shown, temperaturesfor clad needles were dramatically warmer at the 2 mm point versus theunclad needles, and did not drop below 4° C. The 2 mm points of thestandard needles however almost equalize in temperature with the distaltip.

FIGS. 3C and 3D illustrates a detachable probe tip 322 having a hubconnector 324 and an elongated probe 326. The probe tip 322 shares muchof its construction with probe 300. However, the elongated probe 326features a blunt tip 328 that is adapted for blunt dissection of tissue.The blunt tip 328 can feature a full radius tip, less than a full radiustip, or conical tip. In some embodiments, a dulled or truncated needleis used. The elongated probe 326 can be greater than 20 gauge in size,and in some embodiments range in size from 25-30 gauge. As with theembodiments described above, an internal supply tube 330 extends incantilever. However, the exit of the supply tube 330 can be disposed atpositions within the elongated probe 326 other than proximate the blunttip 328. Further, the supply tube 330 can be adapted to create anelongated zone of cooling, e.g., by having multiple exit points forcryofluid to exit from.

The elongated probe 326 and supply tube 330 may be configured toresiliently bend in use, throughout their length at angles approaching120°, with a 5-10 mm bend radius. This may be very challengingconsidering the small sizes of the elongated probe 326 and supply tube330, and also considering that the supply tube 330 is often constructedfrom fused silica. Accordingly, the elongated probe 326 can beconstructed from a resilient material, such as stainless steel, and of aparticular diameter and wall thickness [0.004 to 1.0 mm], such that theelongated probe in combination with the supply tube 330 is not overlyresilient so as to overtly resist manipulation, but sufficiently strongso as to prevent kinking that can result in coolant escaping. Forexample, the elongated probe can be 15 gauge or smaller in diameter,even ranging from 20-30 gauge in diameter. The elongated probe can havea very disparate length to diameter ratio, for example, the elongatedprobe can be greater than 30 mm in length, and in some cases range from30-100 mm in length. To further the aforementioned goals, the supplytube 330 can include a polymer coating 332, such as a polyimide coatingthat terminates approximately halfway down its length, to resist kinkingand aid in resiliency. The polymer coating 332 can be a secondarycoating over a primary polyimide coating that extends fully along thesupply tube. However, it should be understood that the coating is notlimited to polyimide, and other suitable materials can be used. In someembodiments, the flexibility of the elongated probe 326 will vary fromthe proximal end to the distal end. For example, by creating certainportions that have more or less flexibility than others. This may bedone, for example, by modifying wall thickness, adding material (such asthe cladding discussed above), and/or heat treating certain portions ofthe elongated probe 326 and/or supply tube 330. For example, decreasingthe flexibility of elongated probe 326 along the proximal end canimprove the transfer of force from the hand piece to the elongated probeend for better feel and easier tip placement for treatment. Theelongated probe and supply line 330 are may be configured to resilientlybend in use to different degrees along the length at angles approaching120°, with a varying bend radius as small as 5 mm. In some embodiments,the elongated probe 326 will have external markings along the needleshaft indicating the length of needle inserted into the tissue.

FIG. 3E illustrates an exemplary detachable probe tip 322 insertedthrough skin surface SS. As illustrated, the probe tip 322 is insertedalong an insertion axis IA through the skin surface SS. Thereafter, theneedle may be bent away from the insertion axis IA and advanced toward atarget tissue TT in order to position blunt tip 328 adjacent to thetarget tissue TT. In some embodiments, the target tissue may be theinfrapatellar branch of the saphenous nerve. In other embodiments thetarget tissue may be one or more branches of the anterior femoralcutaneous nerve or the lateral femoral cutaneous nerve.

In some embodiments, the probe tip 322 does not include a heatingelement, such as the heater described with reference to probe 300, sincethe effective treating portion of the elongated probe 326 (i.e., thearea of the elongated probe where a cooling zone emanates from) is welllaterally displaced from the hub connector 324 and elongated probeproximal junction. Embodiments of the supply tube are further describedbelow and within commonly assigned U.S. Pub. No. 2012/0089211, which isincorporated by reference.

FIGS. 4A-4C illustrate an exemplary method of creating a hole throughthe skin that allows multiple insertions and positioning of a cryoprobetherethrough. In FIG. 4A a cannula or sheath 1902 is disposed over aneedle 1904 having a tissue penetrating distal end 1908. The cannula mayhave a tapered distal portion 1906 to help spread and dilate the skinduring insertion. The needle/sheath assembly is then advanced into andpierces the skin 1910 into the desired target tissue 1912. The innerpathway of the cannula or sheath 1902 may be curved to assist indirecting the flexible needle 1904, or other probe, into a desiredtissue layer coincident with the desired needle path in the tissue. Oncethe needle/sheath assembly has been advanced to a desired location, theneedle 1904 may be proximally retracted and removed from the sheath1902. The sheath now may be used as an easy way of introducing acryoprobe through the skin without piercing it, and directing thecryoprobe to the desired target treatment area. FIG. 4B shows the sheath1902 in position with the needle 1904 removed. FIG. 4C shows insertionof a cryoprobe 1914 into the sheath such that a blunt tip 1916 of thecryoprobe 1914 is adjacent the target treatment tissue. The cryoprobemay then be cooled and the treatment tissue cooled to achieve any of thecosmetic or therapeutic effects discussed above. In this embodiment, thecryoprobe preferably has a blunt tip 1916 in order to minimize tissuetrauma. In other embodiments, the tip may be sharp and be adapted topenetrate tissue, or it may be round and spherical. The cryoprobe 1914may then be at least partially retracted from the sheath 1902 and/orrotated and then re-advanced to the same or different depth andrepositioned in sheath 1902 so that the tip engages a different portionof the target treatment tissue without requiring an additional piercingof the skin. The probe angle relative to the tissue may also beadjusted, and the cryoprobe may be advanced and retracted multiple timesthrough the sheath so that the entire target tissue is cryogenicallytreated.

While the embodiment of FIGS. 4A-4C illustrates a cryoprobe having onlya single probe, the cryoprobe may have an array of probes. Any of thecryoprobes described above may be used with an appropriately sizedsheath. In some embodiments, the cryoprobe comprises a linear or twodimensional array of probes. Lidocaine or other local anesthetics may beused during insertion of the sheath or cryoprobe in order to minimizepatient discomfort. The angle of insertion for the sheath may beanywhere from 0 to 180 degrees relative to the skin surface, and inspecific embodiments is 15 to 45 degrees. The sheath may be inserted atany depth, but in specific embodiments of treating lines/wrinkles of theface, the sheath may be inserted to a depth of 1 mm to 10 mm, and morepreferably to a depth of 2 mm to 5 mm.

In an alternative embodiment seen in FIG. 4D, the sheath 1902 mayinclude an annular flange 1902 b on an outside surface of the sheath inorder to serve as a stop so that the sheath is only inserted a presetamount into the tissue. The position of the flange 1902 b may beadjustable or fixed. The proximal end of the sheath in this embodiment,or any of the other sheath embodiments may also include a one way valvesuch as a hemostasis valve to prevent backflow of blood or other fluidsthat may exit the sheath. The sheath may also insulate a portion of thecryoprobe and prevent or minimize cooling of unwanted regions of tissue.

Any of the cryoprobes described above may be used with the sheathembodiment described above (e.g. in FIGS. 3B, 4A-4C). Other cryoprobesmay also be used with this sheath embodiment, or they may be used alone,in multi-probe arrays, or combined with other treatments. For example, aportion of the cryoprobe 2006 may be insulated as seen in FIG. 5.Cryoprobe 2006 includes a blunt tip 2004 with an insulated section 2008of the probe. Thus, when the cryoprobe is disposed in the treatmenttissue under the skin 2002 and cooled, the cryoprobe preferentiallycreates a cooling zone along one side while the other side remainsuncooled, or only experiences limited cooling. For example, in FIG. 5,the cooling zone 2010 is limited to a region below the cryoprobe 2006,while the region above the cryoprobe and below the skin 2002 remainunaffected by the cooling.

Different zones of cryotherapy may also be created by differentgeometries of the coolant fluid supply tube that is disposed in thecryoprobe. FIGS. 6-9 illustrate exemplary embodiments of differentcoolant fluid supply tubes. In FIG. 6 the coolant fluid supply tube 2106is offset from the central axis of a cryoprobe 2102 having a blunt tip2104. Additionally, the coolant fluid supply tube 2106 includes severalexit ports for the coolant including circular ports 2110, 2112 near thedistal end of the coolant fluid supply tube and an elliptical port 2108proximal of the other ports. These ports may be arranged in varyingsizes, and varying geometries in order to control the flow of cryofluidwhich in turn controls probe cooling of the target tissue. FIG. 7illustrates an alternative embodiment of a coolant fluid supply tube2202 having a plurality of circular ports 2204 for controlling cryofluidflow. FIG. 8 illustrates yet another embodiment of a coolant fluidsupply tube 2302 having a plurality of elliptical holes 2304, and FIG. 9shows still another embodiment of a coolant fluid supply tube 2402having a plurality of ports ranging from smaller diameter circular holes2404 near the distal end of the supply tube 2402 to larger diametercircular holes 2406 that are more proximally located on the supply tube2402.

As discussed above, it may be preferable to have a blunt tip on thedistal end of the cryoprobe in order to minimize tissue trauma. Theblunt tip may be formed by rounding off the distal end of the probe, ora bladder or balloon 2506 may be placed on the distal portion of theprobe 2504 as seen in FIG. 10. A filling tube or inflation lumen 2502may be integral with or separate from the cryoprobe 2504, and may beused to deliver fluid to the balloon to fill the balloon 2506 up to formthe atraumatic tip.

In some instances, it may be desirable to provide expandable cryoprobesthat can treat different target tissues or accommodate differentanatomies. For example, in FIGS. 11 and 12, a pair of cryoprobes 2606with blunt tips 2604 may be delivered in parallel with one another andin a low profile through a sheath 2602 to the treatment area. Oncedelivered, the probes may be actuated to separate the tips 2604 from oneanother, thereby increasing the cooling zone. After the cryotherapy hasbeen administered, the probes may be collapsed back into their lowprofile configuration, and retracted from the sheath.

In some embodiments, the probe may have a sharp tissue piercing distaltip, and in other embodiments, the probe may have a blunt tip forminimizing tissue trauma. To navigate through tissue, it may bedesirable to have a certain column strength for the probe in order toavoid bending, buckling or splaying, especially when the probe comprisestwo or more probes in an array. One exemplary embodiment may utilize avariable stiff portion of a sleeve along the probe body to provideadditional column strength for pushing the probe through tissue.

An exemplary algorithm 400 for controlling the heater element 314, andthus for transferring heat to the cladding 320, is illustrated in FIG.13. In FIG. 13, the start of the interrupt service routine (ISR) 402begins with reading the current needle hub temperature 404 using atemperature sensor such as a thermistor or thermocouple disposed nearthe needle hub. The time of the measurement is also recorded. This datais fed back to controller 22 where the slope of a line connecting twopoints is calculated. The first point in the line is defined by thecurrent needle hub temperature and time of its measurement and thesecond point consists of a previous needle hub temperature measurementand its time of measurement. Once the slope of the needle hubtemperature curve has been calculated 406, it is also stored 408 alongwith the time and temperature data. The needle hub temperature slope isthen compared with a slope threshold value 410. If the needle hubtemperature slope is less than the threshold value then a treating flagis activated 412 and the treatment start time is noted and stored 414.If the needle hub slope is greater than or equal to the slope thresholdvalue 410, an optional secondary check 416 may be used to verify thatcooling has not been initiated. In step 416, absolute needle hubtemperature is compared to a temperature threshold. If the hubtemperature is less than the temperature threshold, then the treatingflag is activated 412 and the treatment start time is recorded 414 aspreviously described. As an alternative, the shape of the slope could becompared to a norm, and an error flag could be activated for an out ofnorm condition. Such a condition could indicate the system was notheating or cooling sufficiently. The error flag could trigger anautomatic stop to the treatment with an error indicator light.Identifying the potential error condition and possibly stopping thetreatment may prevent damage to the proximal tissue in the form of toomuch heat, or too much cooling to the tissue. The algorithm preferablyuses the slope comparison as the trigger to activate the treatment flagbecause it is more sensitive to cooling conditions when the cryogenicdevice is being used rather than simply measuring absolute temperature.For example, a needle probe exposed to a cold environment wouldgradually cool the needle down and this could trigger the heater to turnon even though no cryogenic cooling treatment was being conducted. Theslope more accurately captures rapid decreases in needle temperature asare typically seen during cryogenic treatments.

When the treatment flag is activated 418 the needle heater is enabled420 and heater power may be adjusted based on the elapsed treatment timeand current needle hub temperature 422. Thus, if more heat is required,power is increased and if less heat is required, power is decreased.Whether the treatment flag is activated or not, as an additional safetymechanism, treatment duration may be used to control the heater element424. As mentioned above, eventually, cryogenic cooling of the needlewill overcome the effects of the heater element. In that case, it wouldbe desirable to discontinue the cooling treatment so that the proximalregion of the probe does not become too cold and cause skin damage.Therefore, treatment duration is compared to a duration threshold valuein step 424. If treatment duration exceeds the duration threshold thenthe treatment flag is cleared or deactivated 426 and the needle heateris deactivated 428. If the duration has not exceeded the durationthreshold 424 then the interrupt service routine ends 430. The algorithmthen begins again from the start step 402. This process continues aslong as the cryogenic device is turned on.

Preferred ranges for the slope threshold value may range from about −5°C. per second to about −90° C. per second and more preferably range fromabout −30° C. per second to about −57° C. per second. Preferred rangesfor the temperature threshold value may range from about 15° C. to about0° C., and more preferably may range from about 0° C. to about 10° C.Treatment duration threshold may range from about 15 seconds to about 75seconds.

It should be appreciated that the specific steps illustrated in FIG. 13provide a particular method of heating a cryogenic probe, according toan embodiment of the present invention. Other sequences of steps mayalso be performed according to alternative embodiments. For example,alternative embodiments of the present invention may perform the stepsoutlined above in a different order. Moreover, the individual stepsillustrated in FIG. 13 may include multiple sub-steps that may beperformed in various sequences as appropriate to the individual step.Furthermore, additional steps may be added or removed depending on theparticular applications.

The heating algorithm may be combined with a method for treating apatient. Referring now to FIG. 14, a method 100 facilitates treating apatient using a cryogenic cooling system having a reusable or disposablehandpiece either of which that can be self-contained or externallypowered with replaceable needles such as those of FIG. 1B and a limitedcapacity battery or metered electrical supply. Method 100 generallybegins with a determination 110 of the desired tissue therapy andresults, such as the inhibition of pain from a particular site.Appropriate target tissues for treatment are identified 112 (a tissuethat transmits the pain signal), allowing a target treatment depth,target treatment temperature profile, or the like to be determined. Step112 may include performing a tissue characterization and/or devicediagnostic algorithm, based on power draw of system 10, for example.

The application of the treatment algorithm 114 may include the controlof multiple parameters such as temperature, time, cycling, pulsing, andramp rates for cooling or thawing of treatment areas. In parallel withthe treatment algorithm 114, one or more power monitoring algorithms 115can be implemented. An appropriate needle assembly can then be mounted116 to the handpiece, with the needle assembly optionally having aneedle length, skin surface cooling chamber, needle array, and/or othercomponents suitable for treatment of the target tissues. Simpler systemsmay include only a single needle type, and/or a first needle assemblymounted to the handpiece.

Pressure, heating, cooling, or combinations thereof may be applied 118to the skin surface adjacent the needle insertion site before, during,and/or after insertion 120 and cryogenic cooling 122 of the needle andassociated target tissue. Non-target tissue directly above the targettissue can be protected by directly conducting energy in the form ofheat to the cladding on a proximal portion of the needle shaft duringcooling. Upon completion of the cryogenic cooling cycle the needles willneed additional “thaw” time 123 to thaw from the internally createdcooling zone to allow for safe removal of the probe without physicaldisruption of the target tissues, which may include, but not be limitedto nerves, muscles, blood vessels, or connective tissues. This thaw timecan either be timed with the refrigerant valve shut-off for as short atime as possible, preferably under 15 seconds, more preferably under 5seconds, manually or programmed into the controller to automaticallyshut-off the valve and then pause for a chosen time interval until thereis an audible or visual notification of treatment completion.

Heating of the needle may be used to prevent unwanted skin damage usingthe apparatus and methods previously described. The needle can then beretracted 124 from the target tissue. If the treatment is not complete126 and the needle is not yet dull 128, pressure and/or cooling can beapplied to the next needle insertion location site 118, and theadditional target tissue treated. However, as small gauge needles maydull after being inserted only a few times into the skin, any needlesthat are dulled (or otherwise determined to be sufficiently used towarrant replacement, regardless of whether it is after a singleinsertion, 5 insertions, or the like) during the treatment may bereplaced with a new needle 116 before the next application ofpressure/cooling 118, needle insertion 120, and/or the like. Once thetarget tissues have been completely treated, or once the cooling supplycanister included in the self-contained handpiece is depleted, the usedcanister and/or needles can be disposed of 130. The handpiece mayoptionally be discarded.

As noted above, suitable target tissues can be selected that include aparticular sensory nerve associated with pain, for example, such as:Myofascial, Fibromylagia, Lateral and Medial epicondylitis,Llio-hypo/llio-inguinal, Pudendal, Pyriformis, Osteo-Arthritis of theKnee, Patellar Tendonitis, Diabetic neuropathies, Carpal Tunnel, PhantomLimb, Migraine, Trigeminal Neuralgia, Occipital Neuralgia, ShoulderArthritis, Shoulder Tendonitis, Suprascapular, Failed Back, Sciatica,Facet, Herniated Disc, Sacoiliac, Sciatic, Morton's Neuroma, and PlantarFasciitis pain.

With respect to knee pain, the infrapatellar branch of the saphenousnerve (ISN), illustrated in FIG. 15, may be targeted for treatmentaccording to embodiments of the present invention. In some embodimentsof the invention, osteoarthritis of the knee or other painful conditionscausing pain in the inferior aspect of the anterior knee may be treatedby targeting the infrapatella branch with cooling treatment.Alternatively, or in addition thereto, the anterior femoral cutaneousnerve and/or the lateral femoral cutaneous nerve may be treated toreduce the knee pain experienced by a patient. The saphenous nervearises as a division of the femoral nerve and leaves the adductor canalbetween the tendons of gracilis and semitendinosus. It then divides intothe main saphenous branch, which continues down to the ankle, and theISN. The ISN traverses the knee below the patella, dividing into threebranches before combining with the anterior branch of the lateralcutaneous nerve of the thigh, the intermediate cutaneous nerves of thethigh and the anterior branch of the medial cutaneous nerve of the thighto form the prepatella plexus.

FIG. 16 depicts the interconnections of the saphenous nerve. Thesaphenous nerve, located about the middle of the thigh, gives off abranch—the ISN—which joins the subsartorial plexus. The ISN pierces thesartorius muscle and fascia lata, and is distributed to the skin infront of the patella. The ISN communicates above the knee with theanterior cutaneous branches of the femoral nerve; below the knee withother branches of the saphenous nerve; and, on the lateral side of theknee, with branches of the lateral femoral cutaneous nerve, forming theplexus patellae. The ISN supplies sensation to the area surrounding andanterior to the knee. Thus, in some embodiments of the presentinvention, cooling treatments may be provided with the devices andmethods disclosed herein to reduce pain sensation in the area of theknee. The anterior femoral cutaneous nerve and the lateral femoralcutaneous nerve may also supply sensation to the area surrounding theknee and may also be treated in some embodiments. In exemplaryembodiments, cooling treatments are provided which reduce the painexperienced by osteo-arthritis patients.

FIG. 17 shows an anatomical illustration of the medial aspect of theknee. The figure illustrates the saphenous nerve giving rise to itsinfrapatella branch in the subartorial canal. The ISN is shown as itpierces the distal sartorius muscle (S) and fascia lata to becomesubcutaneous. The ISN superficially presents an arc-like course betweenthe apex of the patella cranially and tibial tubercle caudally, and endsin the form of two superior and inferior terminal branches.

FIG. 18 shows a medial view of the position and division of the ISN. Asshown in the medial view of the ISN, the ISN emerges through the fascialata medial generally at a level with the inferior pole of the patella.Due to patient to patient variation with regards to both nerve locationand nerve branching, the ISN branch may occur generally between 46 and64 mm from, and may occur on average 55 mm from, the medial border ofthe patella, and may occur generally between 36 and 55 mm from, and mayoccur on average 44 mm from, the medial border of the patellar tendon.The ISN may then divide into three branches medial to the inferior poleof the patella, anterior to the long saphenous vein. These branches ofthe ISN are called, the superior branch, the middle branch, and theinferior branch. The Superior Branch runs transversely just inferior tothe inferior pole of the patella, ending lateral to the patellar tendon.The Middle Branch divides from the Superior Branch medial to the medialborder of the patellar tendon and runs obliquely across the tendon,dividing into its terminal branches at the lateral border. The InferiorBranch is the smallest and runs down in relation to the medial border ofthe tendon, ending at the level of the tibial tuberosity.

Thus in some embodiments, the ISN may be located relative to keyanatomical landmarks. For example, FIG. 19 illustrates exemplaryanatomical landmarks for approximating the location of the ISN. In somemethods, the ISN may be located or approximated as about 55 mm posteriorto the lower pole of the patella. In some methods, the ISN may belocated or approximated as about 44 mm posterior to the medial border ofthe patellar tendon. In some embodiments, the ISN may be located orapproximated as about 55 mm from the lower pole of the patella and about44 mm from the medial border of the patellar tendon. In someembodiments, the ISN position may be approximated based on a location ofthe great saphenous vein. FIG. 19 also illustrates a treatment areawhere cooling may be applied to approximate the location of the ISN.

An example treatment zone is shown in FIG. 20. Here, a treatment zone isshown for treating an infrapatellar branch of a saphenous nerve. Thetreatment zone is shown as an area defined by four borders. A firstboundary (uppermost/superior boundary) of the treatment zone may bedefined by the approximate mid-line of the patella. The second boundary(the lateral boundary) of the treatment zone may be defined as about55-65 mm lateral from the lower pole of the patella. A third boundary(the medial boundary) of the treatment zone may be defined as about 44mm laterally from the medial aspect of the patellar tendon. A fourthboundary (bottommost/inferior boundary) for the treatment zone may bedefined by a line parallel to the first boundary which intersects thetibial tubercule. In some embodiments, the uppermost/superior boundarymay be defined by the superior pole of the patella. Optionally, thelateral boundary may be defined as about 65 mm from the center of thepatella.

The shown treatment zone can be used to treat the infrapatellar branchof a saphenous nerve with high likelihood of success. In one study,which is discussed below, and shown in FIG. 20, a series of treatmentswere performed along the second boundary between the first and fourthboundaries and was successful in placing a needle of a cryogenic deviceinto good proximity with the infrapatellar branch, to successfullyremodel the infrapatellar branch with a cooling zone generated by theneedle. In some cases, treatments can be performed along the thirdboundary to attain an even higher likelihood of success. The treatmentsare performed such that each generated cooling zone is directlyadjacent, or overlapping with a previously created or concurrentlycreated cooling zone. In some cases, a device, such as the one shown inFIG. 3A, having a plurality of needles is used to treat along the secondand/or third boundary. For the sake of redundancy, the treatment zonescan overlap, for example, by placing one needle of the plurality ofneedles in a previously created needle hole, thus linking eachtreatment. In some embodiments of the invention, a treatment guide ortemplate may be fashioned for facilitating the identification of theinfrapatellar branch.

FIG. 21A and FIG. 21B illustrate exemplary guides or templates 500, 501which may be used to approximate a treatment zone. FIG. 21A illustratesan exemplary guide 500 which may be substantially planar and include afirst corner 502, a second corner 504, and a third corner 506. The firstcorner 502 may be aligned with the lower pole of the patella. The secondcorner 504 may be aligned with the medial aspect of the patellar tendon.The third corner may then approximate the location of the infrapatellarbranch. The third corner 506 may be separated by a first distance 508from the first corner 502. The first distance 508 may be between 30 and70 mm. The third corner 506 may also be separated by a second distance510 from the second corner 504. The second distance 510 may be between25 and 60 mm. The template 500 may be constructed from thin flexibleplastic sheet, and may in some embodiments be transparent. In someembodiments, template 500 includes an adhesive backing for temporarilyadhering the template 500 to a skin surface. In some embodiments, thetemplate may contain a transdermal medication, such as anti-inflammatoryand anesthesia (e.g., lidocaine) drugs. An example of such constructionis shown in U.S. Publication No. 2010/0234471, which discloses lidocaintape and is incorporated herein by reference.

FIG. 21B illustrates another embodiment 501 of a treatment guide ortemplate which may be used for approximating a treatment zone fortreating the infrapatellar branch of a patient. The guide 501 includes awindow 512 that defines a treatment zone. Guide 501 may also include afirst indicia 514 and a second indicia 516. Indicia 514 may be alignedwith the midline of the patella for example. Indicia 516 may be alignedwith the tibial tubercle. The medial edge of window 512 may be at afirst distance D1 and the lateral edge of window 512 may be at a seconddistance D2. The first distance D1 may be between 30 and 70 mm. Thesecond distance D2 may be between 25 and 60 mm.

A study was performed on 21 human patients for treatment ofosteoarthritis of the knee, or symptoms resembling OA, using someembodiments of the present invention. Out of the 21 patients, 7 (33%)had one knee treated and 14 (65%) had bilateral treatments. In total, 35knees were treated. The average age of the patients was 55 years with anage range between 30-81 years with a standard deviation of 11.01. TheWestern Ontario and McMaster University Arthritis Index (WOMAC) provideda validated scale for measuring the impact of arthritis on patients whenperforming daily activities. WOMAC of each patient was assessed atbaseline and 7 days post-treatment. Further, a Visual Analog Scale ofPain (VAS) provided a measure of overall patient pain levels usingvisual facial expressions. VAS of each patient was assessed at baseline,pre-treatment, post treatment, and at 7 days and 30 days post-treatment.

The primary endpoint of the study was to provide a significant reductionof pain using validated pain scales. It was found that the patients onaverage received 70-80% post-procedure improvement using these scales. Adevice similar to the one shown in FIG. 3A was used, i.e., a devicehaving 3 cryogenic needles, with each being approximately 6 mm long.Each needle included a conductive coating, coupled to a heater asdescribed with respect to FIG. 3B, that extended approximately 2 mm downthe needle. Treatments times were 60 seconds long each. Typicallybetween four and ten treatments were performed on each knee. Thetreatments were performed using the treatment zone shown in FIG. 20along the second boundary. Treatments typically started at the firstboundary and ended at the fourth boundary but sometimes started at thefourth boundary and ended at the first boundary. In this manner acontinuous treatment fence was created. In some cases, particularly ifthe patient still exhibited pain or other sensations associated withosteoarthritis, a second set of treatments also extended across thefirst boundary. In some cases the starting point along the secondboundary was identified using PENS. In some cases the treatmentcontinued along the treatment line until the patient detected acessation or diminished pain. Cooling zones were made to overlap toincrease the likelihood that the infrapatellar branch of the saphenousnerve was affected, such that second degree nerve injury occurred toinstigate Wallerian degeneration.

The results of this study were surprising and unexpected, as experts inthe field provided professional opinions that the procedure wouldprovide no pain relief. Accordingly, there was no expectation for thelevel of success demonstrated in the study. The results of the study aresummarized in FIG. 22-FIG. 25.

FIG. 22 summarizes the WOMAC score improvement of the 35 knees from 21subjects 7 days after treatment. Scores from assessments were made usingWOMAC Osteoarthritis Index NSR3.1. Pain, stiffness and function subscalescores were calculated by adding the scores within each dimension,according to WOMAC User Guide X. FIG. 22 shows that WOMAC Pain scoresimproved 71% from before the procedure to the 7 day follow-up visit.Further, WOMAC Stiffness scores improved 69% and WOMAC Function scoresimproved 71% when assessed 7 days after treatment. FIG. 23 shows thenumber of subjects reporting improvement in WOMAC Pain score at 7 daysafter treatment. As shown, approximately 80% of the subjects reported a60%-100% improvement in WOMAC Pain Score 7 days after treatment. It wasdetermined that one patient, who reported no improvement after 7 days,was treated in an incorrect position therefore adjusting the position ofthe nerve and the anatomy underlying the skin.

FIG. 24 summarizes the improvement in patient VAS scores followingtreatment. VAS scores decreased for all subjects following treatment. Onaverage the VAS score plot shows an 80% improvement from baselineimmediately post procedure, then 64% improvement at 7 days, and 62% at30 days. FIG. 25 summarizes the duration of benefit from the coolingtreatment. As can be seen, 80% of subjects reported pain relief from thetreatment 56 days after treatment. The duration of the treatment isconsistent with the rate of distal re-innervation of approximately 0.8-1mm per day. Accordingly, it may be possible to provide sustained benefitwith 4-6 treatments per year. FIG. 26 summarizes the percent of kneesreporting anticipated observations at 7 days, 30 days, and 56 dayspost-treatment. A device using a skin warmer, such as the devicedepicted in FIG. 2A or FIG. 3A-3B, may protect the collateral tissueduring treatment of the nerve and thereby reduce the occurrence oferosion, crusting, dimpling, hyperpigmentation, and hypopigmentation.The cladding shown in FIG. 3B may also be used in some embodiments toreduce the occurrence of erosion, crusting, dimpling, hyperpigmentation,and hypopigmentation. FIGS. 27A and 27B summarize the patient'ssubjective satisfaction with the cooling treatment. When asked whetherthey would recommend the treatment to a family member, 95% of patientsresponded affirmatively 7 days after treatment, 94% respondedaffirmatively 30 days after treatment, and 88% responded affirmatively56 days after treatment. When asked whether they would have thetreatment again, 86% responded affirmatively 7 days after treatment, 94%responded affirmatively 30 days after treatment, and 88% respondedaffirmatively 56 days after treatment. Thus temporary pain relief may beprovided to patients suffering from osteoarthritis as indicated by theVAS measurements. Further, such treatments may provide an improvedquality of life as indicated by the WOMAC measurements. Such treatmentsmay also reduce the amount of drug therapy required, postpone invasivesurgeries, and may provide an opportunity for physical rehabilitation(e.g., strength, flexibility, etc.). Furthermore the procedure may beused either pre- or post-operatively. Before total knee replacementsurgery, the procedure may be used to limit pain, allow patients tostrengthen the joint which may improve surgical outcomes. Postsurgically, the procedure may be used to limit the use of opioids orother pain killers and or allow the patient to reduce residualpost-surgical pain.

Although the above described procedures treated the infrapatellar branchof the saphenous nerve using cold to reduce pain and other symptomsassociated with osteo-arthritis, other methods and devices could be usedto temporarily or permanently disable the ISN. Examples include thermalnerve ablation such as with RF energy, or neurolysis using injections ofphenol or ethyl alcohol.

In some embodiments of the present invention, treatment guidance canrely on rigid or boney landmarks because they are less dependent uponnatural variations in body size or type, e.g. BMI. Soft tissues,vasculature and peripheral nerves pass adjacent to the rigid landmarksbecause they require protection and support. By positioning thepatient's skeletal structure in a predetermined position (e.g. knee bent30 degrees or fully extended), one can reliably position the bones,ligaments, cartilage, muscle, soft tissues (including fascia),vasculature, and peripheral nerves. External palpation can then be usedto locate the skeletal structure and thereby locate the pathway andrelative depth of a peripheral nerve targeted for treatment.

A treatment of peripheral nerve tissue to at least −20° C. is sufficientto trigger 2nd degree Wallerian degeneration of the axon and mylinatedsheath. Conduction along the nerve fibers is stopped immediatelyfollowing treatment. This provides immediate feedback as to the locationof the target peripheral nerve or associated branches when theassociated motion or sensation is modified. This can be used to refinerigid landmark guidance of future treatments or to determine whetheraddition treatment is warranted.

Without reliable rigid landmarks, however, the treatment may rely oncreating a block or treatment zone as depicted in FIG. 19 and FIG. 20.Alternatively, by using rigid landmarks, one may be able to direct thetreatment pattern to specific anatomical sites where the peripheralnerve is located with the highest likelihood. Feedback from the patientimmediately after each treatment may verify the location of the targetperipheral nerve and its associated branches. Thus, it should beunderstood that in some embodiments, the use of an electronic nervestimulation device to discover nerve location is not needed or used,since well-developed treatment zones can locate target nerves. This maybe advantageous, due the cost and complexity of electronic nervestimulation devices, which are also not always readily available.

In alternative embodiments of the invention, one could use an electronicnerve stimulation device (either transcutaneous or percutaneous) tostimulate the target peripheral nerve and its branches. Withtranscutaneous electric nerve stimulation (TENS) the pathway of thenerve branch can be mapped in an X-Y coordinates coincident with theskin surface. The Z coordinate corresponding to depth normal to the skinsurface can be inferred by the sensitivity setting of the electricalstimulation unit. For example, a setting of 3.25 mA and pulse durationof 0.1 ms may reliably stimulate the frontal branch of the temporalnerve when it is within 7 mm of the skin surface. If a higher currentsetting or longer pulse duration is required to stimulate the nerve,then the depth may be >7 mm. A percutaneous electrical nerve stimulator(PENS) can also be used to locate a target peripheral nerve. Based onrigid anatomical landmarks, a PENS needle can be introduced through thedermis and advanced into the soft tissues. Periodic stimulating pulsesat a rate of 1-3 Hz may be used to stimulate nerves within a knowndistance from the PENS needle. When the target nerve is stimulated, thesensitivity of the PENS can be reduced (e.g. lowering the currentsetting or pulse duration) narrowing the range of stimulation. When thenerve is stimulated again, now within a smaller distance, the PENSsensitivity can be reduced further until the nerve stimulation distanceis within the therapy zone dimensions. At this point, the PENS needlecan be replaced with the focused cold therapy needle(s) and a treatmentcan be delivered. The PENS and focused cold therapy needles can beintroduced by themselves or through a second larger gage needle orcannula. This may provide a rigid and reproducible path when introducinga needle and when replacing one needle instrument with another. A rigidpathway may guide the needle to the same location by preventing needletip deflection, which could lead to a misplaced therapy and lack ofefficacy.

While many of the examples disclosed herein related to puncturing theskin in a transverse manner to arrive at a target sensory nerve, othertechniques can be used to guide a device to a target sensory nerve. Forexample, insertion of devices can be made parallel to the surface of theskin, such that the (blunted) tip of the device glides along aparticular fascia to arrive at a target sensory nerve. Such techniquesand devices are disclosed in U.S. Pub. No. 2012/0089211, the entirety ofwhich is incorporated by reference. Possible advantages may include asingle insertion site, and guidance of a blunt tip along a layer commonwith the path or depth of the target infrapatellar saphenous nerve. Thistechnique may be a position-treatment—thaw, reposition treatment, thaw,etc.

While the exemplary embodiments have been described in some detail forclarity of understanding and by way of example, a number ofmodifications, changes, and adaptations may be implemented by persons ofordinary skill in the art after reading the disclosure provided herein.Hence, the scope of the present invention is limited solely by theclaims as follows.

What is claimed is:
 1. A method for reducing knee pain experienced by apatient, the method comprising: determining a location of a treatmentzone with reference to a skin surface proximate to a nerve associatedwith pain of a knee of a leg; inserting at least one needle of atreatment device through the skin surface and into the treatment zone;and applying a series of adjacent treatments along a treatment line, thetreatment line formed by the series of adjacent treatments beingtransverse to a length of the nerve, the series of adjacent treatmentsbeing applied by: positioning the at least one needle at a plurality ofpositions along the treatment line through a plurality of adjacentaccess sites in the skin surface for applying the series of adjacenttreatments that traverse the nerve such that at least one of theplurality of positions where the at least one needle is positioned isadjacent to the nerve; and activating treatment at each of the pluralityof positions such that treatment is applied at each of the plurality ofpositions along the treatment line and about the nerve, thereby blockingsignals along the nerve and eliminating or reducing severity of pain. 2.The method of claim 1, wherein the pain is associated withosteoarthritis of the knee, and wherein the nerve is an infrapatellarbranch of a saphenous nerve, a lateral femoral cutaneous nerve, or ananterior femoral cutaneous nerve.
 3. The method of claim 1, whereinthermal energy is used to treat the nerve.
 4. The method of claim 3,wherein RF is used to create the thermal energy.
 5. The method of claim1, wherein the treatment is with an injection.
 6. The method of claim 5,wherein the injection is phenol.
 7. The method of claim 5, wherein theinjection is ethyl alcohol.
 8. The method of claim 1, wherein eachtreatment of the series of adjacent treatments generates a correspondingtreatment zone and wherein a first generated corresponding treatmentzone overlaps a second generated corresponding treatment zone.
 9. Themethod of claim 1, wherein cryogenic cooling is used to treat the nerve.10. The method of claim 1, wherein body landmarks are used to determinethe location of the treatment zone.
 11. The method of claim 10, whereinthe treatment zone has a superior boundary defined by a midline of apatella of the leg.
 12. The method of claim 10, wherein the treatmentzone has an inferior boundary defined by a tibial tubercle of the leg.13. The method of claim 10, wherein the treatment zone has a medialboundary defined by a distance lateral to a medial aspect of a patellartendon of the leg.
 14. The method of claim 10, wherein the treatmentzone has a lateral boundary defined by a distance lateral to a lowerpole of a patella of the leg.
 15. The method of claim 10, wherein thetreatment zone is defined by a medial boundary, a lateral boundary, asuperior boundary, and an inferior boundary, wherein the treatment lineextends substantially parallel to the medial boundary such that thetreatment is applied along the medial boundary between the superior andinferior boundaries.
 16. The method of claim 10, wherein the treatmentzone is defined by a medial boundary, a lateral boundary, a superiorboundary, and an inferior boundary, and wherein the treatment is appliedalong the medial and lateral boundaries between the superior andinferior boundaries.
 17. The method of claim 1, wherein the cryogenicdevice comprises a plurality of needles, and the plurality of needles ofthe cryogenic device are inserted into the treatment zone.
 18. Themethod of claim 1, further comprising: applying a second series ofadjacent treatments along a second treatment line, the second treatmentline formed by the series of adjacent treatments being transverse to alength of the nerve at a second location, the second series of adjacenttreatments being applied by: positioning the at least one needle at aplurality of positions along the second treatment line through aplurality of adjacent access sites in the skin surface for applying thesecond series of adjacent treatments that traverse the nerve at thesecond location such that at least one of the plurality of positionswhere the at least one needle is positioned is adjacent to the nerve;and activating treatment at each of the plurality of positions such thattreatment is applied at each of the plurality of positions along thesecond treatment line and about the nerve, thereby blocking signalsalong the nerve and eliminating or reducing severity of pain.
 19. Themethod of claim 18, wherein the second treatment line extendssubstantially parallel to the first treatment line.
 20. The method ofclaim 18, wherein second treatment line extends substantiallyperpendicular to the first treatment line.
 21. The method of claim 8,wherein the treatment device comprises a pair of needles and whereinpositioning the at least one needle comprises positioning the pair ofneedles through first and second access sites in the skin surface togenerate the first generated corresponding treatment zone and throughthe second access site and a third access site to generate the secondgenerated corresponding treatment zone such that the first and secondgenerated corresponding treatment zones overlap.